To get the result we have to transform given formula into y=ax+b form.
Lets do this
5x+3y=6 /-5x (subtract 5x both sides)
3y=-5x+6 /:3 (divide both sides by 3)
y=

In form y=ax+b we know that a is slope and b is y intersect. We can read from our transformed equation that slope a=

and its the result